Re-installation of booster pump

[toadhall]

Hi,
My grundfos 2bar -ve head twin pump packed up and I have bought a like for like replacement.

The old pump (and new one) is located in the basement on the floor next to the hot water cylinder as it should be.

Both the two inlet and two outlet pipes to the pump have a valve allowing for easy removal and replacement of the pump. All good.

When I attach the new pump, is there a technique for ensuring that air does not get trapped in the system. i.e. shall I open say the outlet valves first to flood the pump or perhaps the inlet valves or does it not matter? Should the taps/shower head be open or closed? When can I switch the pump on?


Any advive would be much appreciated.
t

 

[Dan Robinson]

Not worth worrying about... crack on.

 

[toadhall]

That's the kind of advice I like!

Perfect thanks
t

 

[Dan Robinson]

8)

 

[kvsalamander]

To be honest i would really follow the manufactures guidlines on how to commission the pump.

usually this would mean having the pump full of water before turning it on. Easiest way would be to put the outlet hoses in a bucket first and turn the inlets on with the electric off to flood the pump first.

cheers

 

[toadhall]

As the pump is the lowest part of the entire plumbing system, surely by hooking up the hoses (which run vertically upwards from the pump) and opening the valves, the pump will be automatically flooded by all the water that is in the pipes above the valve points.

So no need for the bucket?

I was worried about air (which used to be in the new pump) rising upwards through the system as pump floods.

 

[Dan Robinson]

Yes, you will be fine if you open the valves before powering the pump. technically KVS is right of course, but in practice....

The air will soon get force out from a vent or tap.

 

[kvsalamander]

Possibly, however you have a negative head pump, so you wont get a natural flow through the entire system under gravity.

Personally i would open the outlets into a bucket under gravity at the pump, re-connect back up and open the highest point in the installation, allow the gravity flow to fill up the system as much as possible, then fire up the pump

However that's a personal thing and would consult the manufacturers installation guide and check the commissioning pages.

regards

 

[Dan Robinson]

His pump is at the lowest point - negative or not, the impellers should flood when he opens the valves??

 

[kvsalamander]

Possibly, however the way i suggest is fail proof and the safest way of doing things, its not worth taking any risks with an expensive piece of equiptment.

It is always best to consult manufactures guidelines